package com.yunxiao.cloud.common.config;

import org.springframework.beans.factory.annotation.Value;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
import org.springframework.scheduling.concurrent.ThreadPoolTaskExecutor;

import java.util.concurrent.Executor;
import java.util.concurrent.ThreadPoolExecutor;

/**
 * @description: 定义异步任务执行线程池
 * @author: yunxiao
 * @date: 2020/1/16 10:54
 * @version: V1.0
 **/
@Configuration
public class TaskPoolConfig {

    @Value("${task.pool.executor.corePoolSize}")
    private int corePoolSize;

    @Value("${task.pool.executor.maxPoolSize}")
    private int maxPoolSize;

    @Value("${task.pool.executor.queueCapacity}")
    private int queueCapacity;

    @Value("${task.pool.executor.keepAliveSeconds}")
    private int keepAliveSeconds;

    @Value("${task.pool.executor.threadNamePrefix}")
    private String threadNamePrefix;

    @Value("${task.pool.executor.waitForJobsToCompleteOnShutdown}")
    private boolean waitForJobsToCompleteOnShutdown;

    @Value("${task.pool.executor.awaitTerminationSeconds}")
    private int awaitTerminationSeconds;

    @Bean("taskExecutor")
    public Executor taskExecutor() {
        ThreadPoolTaskExecutor executor = new ThreadPoolTaskExecutor();
        // 核心线程数10：线程池创建时候初始化的线程数
        executor.setCorePoolSize(corePoolSize);
        // 最大线程数20：线程池最大的线程数，只有在缓冲队列满了之后才会申请超过核心线程数的线程
        executor.setMaxPoolSize(maxPoolSize);
        // 缓冲队列200：用来缓冲执行任务的队列
        executor.setQueueCapacity(queueCapacity);
        // 允许线程的空闲时间60秒：当超过了核心线程数之外的线程在空闲时间到达之后会被销毁
        executor.setKeepAliveSeconds(keepAliveSeconds);
        // 线程池名的前缀：设置好了之后可以方便定位处理任务所在的线程池
        executor.setThreadNamePrefix(threadNamePrefix);
        /*
        线程池对拒绝任务的处理策略：这里采用了CallerRunsPolicy策略，
        当线程池没有处理能力的时候，该策略会直接在 execute 方法的调用线程中运行被拒绝的任务；
        如果执行程序已关闭，则会丢弃该任务
         */
        executor.setRejectedExecutionHandler(new ThreadPoolExecutor.CallerRunsPolicy());
        // 设置线程池关闭的时候等待所有任务都完成再继续销毁其他的Bean
        executor.setWaitForTasksToCompleteOnShutdown(waitForJobsToCompleteOnShutdown);
        // 设置线程池中任务的等待时间，如果超过这个时候还没有销毁就强制销毁，以确保应用最后能够被关闭，而不是阻塞住。
        executor.setAwaitTerminationSeconds(awaitTerminationSeconds);
        return executor;
    }
}
